Workers should be back on site at the long-delayed Silver Spring Transit Center on Wednesday to begin to repair the structure, Montgomery County officials said.

David Dise, director of the county’s Department of General Services, said the first round of repairs includes the removal of concrete slabs that did not contain reinforcements and testing concrete that will be used to replace the slabs at the $120 million transit hub.

Some concrete sections of the transit center were installed without metal beams and post tensioning wires, which ensure the concrete’s strength. Dise said those sections will be taken out while a test mock-up will be done simultaneously with the concrete that will be used to replace the existing concrete slabs.

The transit center, located at the corner of Colesville Road and Wayne Avenue in downtown Silver Spring, was slated to open in 2011, but a series of cracks found in the structure and disparities in the thickness of the concrete have delayed the project’s opening by two years so far. It is still unclear when the center will be open for business.

Dise said last week that the concrete sections known as “pour strips” need to be fixed before the remainder of repairs can be carried out. Those fixes include an “overlay” that will be chemically bonded to the existing concrete to ensure the proper concrete strength and thickness, and to fix some of the cracking found in the structure.

The county was cleared July 8 to begin fixing the concrete slabs at the facility, County Executive Isiah Leggett (D) told members of the Silver Spring Citizens Advisory Board at its monthly meeting at the Silver Spring Civic Building that night. He also said permits for the remainder of the fixes will be released by the end of July.

Tina Slater, president for Action Committee for Transit, said that while she is glad that work is starting, she is worried about how long the repair schedule will be.

“We just have no idea when it will end,” she said last week. “The whole project has been a disaster.”